Dynamic Compressive Behaviours of Stainless-Clad Bimetallic Steel under High Temperatures

To study the dynamic performance of stainless-clad (SC) bimetallic steel under coupling actions of high temperature and strain rate, a total of 72 compression experiments were designed and conducted at four strain rates (0.001, 1000, 2000 and 3000 s_ 1) and four temperatures varying from 20 & DEG;C to 600 & DEG;C. The deformation patterns, stress versus strain responses, as well as strain rate and temperature effects were obtained and analyzed. Experimental results indicated that the dynamic compression performances of SC bimetallic steel were sensitive to both temperature and strain rate. The dynamic yield strength at 3000 s_ 1 was approximately 1.7 times than that under quasi-static conditions, while reduced by 24-35%, 37-50% and 52-62% when temperatures rose from 20 & DEG;C to 200 & DEG;C, 400 & DEG;C and 600 & DEG;C, respectively. Moreover, the strain rate sensitivity increased with the growing strain rate and temperature. The observation of microstructures showed that the grain dimensions declined with increase in strain rate or a decreased temperature. According to test data, a modified Johnson-Cook model was developed for predicting the stress versus strain response of the SC bimetallic steel subjected to combined actions of high strain rate and elevated temperature (20-600 & DEG;C), in which the influences of temperature softening, strain-rate strengthening and strain hardening were considered.